A major trend in wireless communication systems is the investigation of radio-frequency (RF) transceivers that can be widely tuned across frequency bands. However, wideband receiver front-ends have to handle interference signals that are much larger than those in conventional narrowband receivers due to the lack of tunable high-front-end RF filters.
Out-of-band-modulated transmitter self-interference (or TX leakage) due to reduced antenna/duplexer isolation in many circuits imposes challenges, including cross-modulation, second-order inter-modulation and TX noise in the receiver (RX) band.
Accordingly, circuits for reducing out-of-band-modulated transmitter self-interference are desirable.